Oil Type for a Craftsman 550 Series Lawnmower

The Sears Craftsman 550 Series walk-behind, gasoline-powered lawnmower is a four-wheeled, single-cylinder, four-cycle rotary lawnmower with a 21-inch cutting swath. Fresh motor oil is important for this mower’s Briggs and Stratton engine to have a long life, which is why the manufacturer specifies replacing the crankcase oil with 20 ounces of new oil annually or after every 25 hours of the mower's operation. A particular engine oil must be used, however.

Engine Oil Type

The owner’s manual of the Craftsman 550 Series lawnmower specifies using a detergent-type motor oil with an API service classification of SG-SL. The viscosity grade to use depends on the air temperature. If you will operate your mower at a temperature above 32 degrees Fahrenheit, then use SAE 30 weight motor oil. If you will run the mower at a temperature below 32 degrees, use SAE 5W-30 multiweight motor oil. Multiweight oil can be used at warmer temperatures, but check the mower's oil level more frequently than normal if you use a multiweight oil because it has an increased consumption rate.